Presently, the systems available to refine clay, in particular bentonite clay, are vertical batch-type systems. In these vertical batch-type systems, a fixed amount of clay and water are combined in a large clarifier to form a clay slurry. A mixing blade is inserted into the clay slurry and is rotated at a high revolution per minute (RPM). As the clay slurry is mixed, solid non-clay material such as rock is filtered out of the clay by a screen. These high RPM blades continuously hit rocks and other solid non-clay material in the clay slurry creating large impact forces which cause severe damage to the blades. This damage requires continual blade maintenance and replacement. Also, the screen used in the filtering process is susceptible to damage by the rock and is in continual need of repair or replacement as well.
Besides the maintenance problems associated with these vertical batch-type systems, these systems, since they are batch systems and not continuous, are also inefficient and slow down the overall refining process.